eBay compressor

[Richard Lee]

There is also the O ring for the black filter housing, it may be leaking, and seem like the air is coming from the QD. I've had to replace this O ring twice now. One leaked, one blew out...

Yeah! It did make it seem like the leak was at the QD! I could feel the air down at the QD..
When I checked it (just now), I said, "that can't be leaking", because I couldn't feel any air coming out of the housing..
Then I put some talcum powder on the fittings. The results looked odd. Flipped it upside down and did it again!
The air coming past that large (30mm?) O-ring blew away some of the powder.

I had visually inspected that O-ring and it seemed fine (didn't remove it). I just replaced it, and it still looks okay.. Why?
Did a quick test and got some good pressure.. Maybe there was some small piece of fuzz on the O-ring.?.

The other day, I took the filter housing apart to take a picture of the filter media. Maybe that's when
something got into the seal and worked it's way under the O-ring.. Before I took that photo, everything was fine!

Thanks for that tip! "and seem like the air is coming from the QD."    That helped a lot!

Cheers,
Rich

[SteveUK]

Still working my way through all the posts in this thread - but as I've seen these small compressors as per original post advertised as up to 500cc bottle only and also seen same compressor 7 liter fill time on other ads - I'm wondering if anybody has tried radiator cooling to enable the filling of scuba tanks

I wonder about these mini radiators with fans:
aliexpress.com/af/aluminium-radiator-fan-water.html

[Trigger_Finger]

Still working my way through all the posts in this thread - but as I've seen these small compressors as per original post advertised as up to 500cc bottle only and also seen same compressor 7 liter fill time on other ads - I'm wondering if anybody has tried radiator cooling to enable the filling of scuba tanks

I wonder about these mini radiators with fans:
aliexpress.com/af/aluminium-radiator-fan-water.html

Radiator cooling has been done somebody did post a picture of it somewhere in GTA. You just have to look for that thread.

[SteveUK]

What is the max size tank that these compressors can be realistically used to fill ?

Can they do scba 66cf 88cf ?
or more for the little ones ?

They are for paintball tanks, which I believe are usually 0.4 liter and buddy bottles used on air rifles typically 0.5 liter

If you fill a bigger tank in stages I see no problem - UK supplier to Amazon UK states the maximum bottle size is 0.5 liter 300 bar - I suppose that's what they calculate is safe for continuous use without over-heating compressor

[SteveUK]

Ken,

What is a 144 CC tank? That seems tiny to me since a 13ci ninja is 213cc.

I'm considering one of these to top off my scuba after each shooting session (3000 PSI 80 CF, maybe ~200 psi top off) but if it takes an hour to fill a bottle half the size of a ninja bottle, that might not be quite enough....

Definitely not 144cc - if it is metric measurement on the tank then more like 14.4 liter - maybe marking is 144?

[SteveUK]

Bet there is an omega air compressor on the web under a different name, color?😳

And the link to it is?

this one which looks just like my omega but different color.  no price😳😎
link removed

There is a price now - $800 but minimum order is 10 units, so $8000 dollars investment - don't know what the shipping cost is

Looks like Omega latest version - except the controls for self-draining are missing - just a blanking plate - guess it is pre-set intervals

[SteveUK]

Have a minor problem with the gauge. Needle is bouncing around and when I bleed the system from filling sometimes the gauge will not return back to zero. Have to tap the gauge to make the needle go back to zero.the needle Reads 10 psi off from zero and I have to tap the gauge to get needle to zero. I'm going to have to get a new gauge that is liquid filled. I believe the liquid filled gauge will help with the vibration of the compressor while filling. The gauge still works but due to the vibration the gauge is not accurate any more.

I did watch an unboxing/demo/teardown video that said they cannot ship these compressors with batteries or any oil - including oil in the gauge - and that you are supposed to add silicone oil to the gauge yourself before operating - pretty sure it was that big German youtube guy - called Spraug or something - does slingshot, crossbow and air weapon videos

[SteveUK]

Hummm, I just noticed. Your gauge is not glycerin filled? Mine is... Maybe they didn't use filled gauges in the early production models? Or, did yours maybe leak?

They are not supposed to ship anything with oil in it - including gauges - you are supposed to add your own silicone oil

[avator]

This is true.... I hear folks complain about items coming to the US without batteries.... well, they're not supposed to have batteries in them. Lots of legal stuff goes into International shipping, including higher rates for shipping hazardous materials. Batteries are caustic among other things.

[SteveUK]

I'm surprised that nobody has fabricated a self-contained liquid cooling option (Radiator, fan, reservoir, tubing, fittings, aluminum mount, propylene glycol/distilled water mix, and a 12v out to Molex) . I've built plenty of computers with them.

Could be done and would work - but would require some sort of automation - start, stop, vent, start, stop, vent, until filling completed - similar to how a refrigerant dehumidifier works

I've now convinced myself that these compressors are not suitable for anything other than topping up air rifles - the twin cylinder compressors are much better - the one I've got my eye on has been sold previously on Amazon under the DAVV brand name - but now only available from AliExpress type sites

[SteveUK]

I got the name wrong on the type of compressor I'm now looking at - looks like DAVV painted on the compressor but is actually DAVY

These are now listed as unavailable on Amazon - were $800 or more

Not sure about the supplier reputation but several on AliExpress less than $450 delivered

Looks very similar to the twice the price "in a frame" compressors

Example: aliexpress.com/item/Double-Cylinder-Electric-Air-Pump-Paintball-Air-Compressor-High-Pressure-PCP-Rifle-Air-Pump/32816515130.html

[imadunatic]

I've now convinced myself that these compressors are not suitable for anything other than topping up air rifles - the twin cylinder compressors are much better - the one I've got my eye on has been sold previously on Amazon under the DAVV brand name - but now only available from AliExpress type sites

I've been unsuitably topping off my 80cf scuba ever since I received my compressor.... Makes 50psi/minute, even after running 20 minutes it never got above 55c with a 5 gallon bucket of water. Personally, I could ask for no more for $327 to my door.

[SteveUK]

I got the name wrong on the type of compressor I'm now looking at - looks like DAVV painted on the compressor but is actually DAVY

I've now found the manufacturer - they make some serious looking gear - davyenergy.com

[SteveUK]

I've been unsuitably topping off my 80cf scuba ever since I received my compressor.... Makes 50psi/minute, even after running 20 minutes it never got above 55c with a 5 gallon bucket of water. Personally, I could ask for no more for $327 to my door.

Yes, I know it can be done - but they were not designed for it

The supplier to Amazon UK state max 0.5 liter tank for the single cylinder compressor and 6.8 liter tank for twin cylinder compressor - your tank is about 12 liter - I know you are just topping up but still way over what a single cylinder compressor is meant for - seems a lot of people's compressors would overheat badly, doing what you are doing

[SteveUK]

It appears that the cheapo twin cylinder compressors on AliExpress that I like are knock-offs of DAVY - which have all black cylinders - cheapo ones are bright aluminum, so I don't know who are making them

An interesting tank filling chart and pictures of genuine DAVY cng-scuba.com/index.php?route=product/product&product_id=11928

[SteveUK]

Found a demo video of the twin cylinder compressor like on AliExpress - not sure if mylond make them or just sell them

Running time 2min 20sec small bowl of water = temperature 47 degrees

youtu.be/_eGvJVrGYuY

[imadunatic]

Yes, I know it can be done - but they were not designed for it

The supplier to Amazon UK state max 0.5 liter tank for the single cylinder compressor and 6.8 liter tank for twin cylinder compressor - your tank is about 12 liter - I know you are just topping up but still way over what a single cylinder compressor is meant for - seems a lot of people's compressors would overheat badly, doing what you are doing

I hear a lot of people (yourself included) that don't own and have never actually seen one of these compressors in person state that these can't and or won't and or shouldn't fill scuba tanks. To many, that means that these are automatically not an option for anything except topping off guns and they immediately feel they need to move on to much larger and or more expensive machines when most of the time they would simply be topping off cylinders also.

If you were filling from zero, and if you didn't ice your 5 gallon water jug and if you didn't do maintenance then bad things can and do happen as we've seen (though so far it seems to be Tuxing brand compressors that have had the reported afflictions, but the reports I've seen on those failures was less than scientific).

I know I am not the only one successfully topping off scuba tanks, and many have been doing it MUCH longer than I have, but I can assure you that I and anyone else who is "testing" these little compressors would immediately report a failure because everyone (including many of us who bought them) is chomping at the bit to determine the MTBF in as many different use case scenarios as we can dream up because they seem too cheap.

Also, I see many assume because they paid upwards of $1000 for an air compressor, that it must be better than the cheaper compressors. While this may be true, at the end of the day you are still buying a chinese air compressor from a chinese manufacturer that may or may not provide support in 2 years, and may or may not supply parts in 2 years and may or may not still work in 2 years.

Eventually every mechanical thing will wear out and require parts and it doesn't care how much cash you piled up for it when you swiped your card. The fact is we don't have enough history on any of them to determine what their lifespan is nor what the weak point is that potentially all of these compressors from the $1300 carette down to the $300 yong heng all share.

[bowdoc64]

Guy on YouTube did a review and said the pump is fine no real issues. You need an external water supply for cooling

[kzz1kaw]

Shorty true story. I am a collector of switchblades and out the front (otf) balisong ( butterfly) knives since childhood. (Military gave out the gerber and h&k otf and switchblades)high end knives such As microtech gerber h&k etc. found a website China of course that sells exact copies of the mention knives right down to the packaging 😳 so I ordered theses knives and a month later, they arrived in the mail. I was shocked to see how the Chinese copied with great detail down to the weight packaging side by side had to write  a c on the box to be able to tell the copy vs the real one😳 I call the microtech manufacturer and was told yes they are aware of the fakes because they get the fakes in for warrenty work and they can tell some way that it is not the real deal and the customer does not get the knife back. Microtech will not ship overseas to customers because of this problem. When it comes to the high end compressor davvy etc in my opinion, I  truly believe that the compressors are made in China with the manufacturer label shipped to the factory and selling at a high price😎

[avator]

ALL need some sort of cooling. If I didn't accidently luck into the dual cylinder compressor that I have, I would have one of these single cylinder ones. I would have probably joined the "I got burned" club at least once and may even be still waiting for my refund. But at the end of the day I would have one of these smaller Chinese compressors. For no other reason but it's what I am willing to invest in this part of my hobby..... key word being "hobby". It would be at that point that I would make my decision as to how I chose to use it. Whether directly filling guns, filling my 80 and 100 cf scuba tanks or investing in a smaller capacity larger psi carbon "buddy type" tank. The thing is, the compressor is so portable and so efficient for filling guns directly I doubt I'd be filling larger tanks regularly unless I'm spending a whole day or 2 in a remote location. With a bit of common sense I could see these compressors as very useful and dependable. I can get from point A to B on a moped or a Harley. I am fortunate enough to have the Harley. If not, I might be sporting a scooter. I see folks going down the road on a scooter with the same grin I get from my Harley. I'm pretty sure they do the same basic maintenance as I do to insure they get there and back.